<?php
/**
 *--------------------------------------------------------------------
 *
 * Sub-Class - EAN-8
 *
 * EAN-8 contains
 *	- 4 digits
 *	- 3 digits
 *	- 1 checksum
 *
 * The checksum is always displayed.
 *
 *--------------------------------------------------------------------
 * Copyright (C) Jean-Sebastien Goupil
 * http://www.barcodephp.com
 */
include_once('BCGBarcode1D.php');

class BCGean8 extends BCGBarcode1D {
	protected $labelLeft = null;
	protected $labelRight = null;

	/**
	 * Constructor.
	 */
	public function __construct() {
		parent::__construct();

		$this->keys = array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9');

		// Left-Hand Odd Parity starting with a space
		// Right-Hand is the same of Left-Hand starting with a bar
		$this->code = array(
			'2100',	/* 0 */
			'1110',	/* 1 */
			'1011',	/* 2 */
			'0300',	/* 3 */
			'0021',	/* 4 */
			'0120',	/* 5 */
			'0003',	/* 6 */
			'0201',	/* 7 */
			'0102',	/* 8 */
			'2001'	/* 9 */
		);
	}

	/**
	 * Draws the barcode.
	 *
	 * @param resource $im
	 */
	public function draw($im) {
		$c = strlen($this->text);
		
		// Checksum
		$this->calculateChecksum();
		$temp_text = $this->text . $this->keys[$this->checksumValue];
		
		// Starting Code
		$this->drawChar($im, '000', true);
		
		// Draw First 4 Chars (Left-Hand)
		for ($i = 0; $i < 4; $i++) {
			$this->drawChar($im, $this->findCode($temp_text[$i]), false);
		}
		
		// Draw Center Guard Bar
		$this->drawChar($im, '00000', false);
		
		// Draw Last 4 Chars (Right-Hand)
		for ($i = 4; $i < 8; $i++) {
			$this->drawChar($im, $this->findCode($temp_text[$i]), true);
		}

		// Draw Right Guard Bar
		$this->drawChar($im, '000', true);
		$this->drawText($im, 0, 0, $this->positionX, $this->thickness);

		if ($this->isDefaultEanLabelEnabled()) {
			$dimension = $this->labelRight->getDimension();
			$this->drawExtendedBars($im, $dimension[1] - 2);
		}
	}

	/**
	 * Returns the maximal size of a barcode.
	 *
	 * @param int $w
	 * @param int $h
	 * @return int[]
	 */
	public function getDimension($w, $h) {
		$startlength = 3;
		$centerlength = 5;
		$textlength = 8 * 7;
		$endlength = 3;

		$w += $startlength + $centerlength + $textlength + $endlength;
		$h += $this->thickness;
		return parent::getDimension($w, $h);
	}

	/**
	 * Adds the default label.
	 */
	protected function addDefaultLabel() {
		if ($this->isDefaultEanLabelEnabled()) {
			$this->processChecksum();
			$label = $this->getLabel();
			$font = $this->font;

			$this->labelLeft = new BCGLabel(substr($label, 0, 4), $font, BCGLabel::POSITION_BOTTOM, BCGLabel::ALIGN_LEFT);
			$labelLeftDimension = $this->labelLeft->getDimension();
			$this->labelLeft->setOffset(($this->scale * 30 - $labelLeftDimension[0]) / 2 + $this->scale * 2);

			$this->labelRight = new BCGLabel(substr($label, 4, 3) . $this->keys[$this->checksumValue], $font, BCGLabel::POSITION_BOTTOM, BCGLabel::ALIGN_LEFT);
			$labelRightDimension = $this->labelRight->getDimension();
			$this->labelRight->setOffset(($this->scale * 30 - $labelRightDimension[0]) / 2 + $this->scale * 34);

			$this->addLabel($this->labelLeft);
			$this->addLabel($this->labelRight);
		}
	}

	/**
	 * Checks if the default ean label is enabled.
	 *
	 * @return bool
	 */
	protected function isDefaultEanLabelEnabled() {
		$label = $this->getLabel();
		$font = $this->font;
		return $label !== null && $label !== '' && $font !== null && $this->defaultLabel !== null;
	}

	/**
	 * Validates the input.
	 */
	protected function validate() {
		$c = strlen($this->text);
		if ($c === 0) {
			throw new BCGParseException('ean8', 'No data has been entered.');
		}

		// Checking if all chars are allowed
		for ($i = 0; $i < $c; $i++) {
			if (array_search($this->text[$i], $this->keys) === false) {
				throw new BCGParseException('ean8', 'The character \'' . $this->text[$i] . '\' is not allowed.');
			}
		}

		// If we have 8 chars just flush the last one
		if ($c === 8) {
			$this->text = substr($this->text, 0, 7);
		} elseif ($c !== 7) {
			throw new BCGParseException('ean8', 'Must contain 7 digits, the 8th digit is automatically added.');
		}

		parent::validate();
	}

	/**
	 * Overloaded method to calculate checksum.
	 */
	protected function calculateChecksum() {
		// Calculating Checksum
		// Consider the right-most digit of the message to be in an "odd" position,
		// and assign odd/even to each character moving from right to left
		// Odd Position = 3, Even Position = 1
		// Multiply it by the number
		// Add all of that and do 10-(?mod10)
		$odd = true;
		$this->checksumValue = 0;
		$c = strlen($this->text);
		for ($i = $c; $i > 0; $i--) {
			if ($odd === true) {
				$multiplier = 3;
				$odd = false;
			} else {
				$multiplier = 1;
				$odd = true;
			}
	
			if (!isset($this->keys[$this->text[$i - 1]])) {
				return;
			}

			$this->checksumValue += $this->keys[$this->text[$i - 1]] * $multiplier;
		}

		$this->checksumValue = (10 - $this->checksumValue % 10) % 10;
	}

	/**
	 * Overloaded method to display the checksum.
	 */
	protected function processChecksum() {
		if ($this->checksumValue === false) { // Calculate the checksum only once
			$this->calculateChecksum();
		}

		if ($this->checksumValue !== false) {
			return $this->keys[$this->checksumValue];
		}

		return false;
	}

	/**
	 * Draws the extended bars on the image.
	 *
	 * @param resource $im
	 * @param int $plus
	 */
	private function drawExtendedBars($im, $plus) {
		$rememberX = $this->positionX;
		$rememberH = $this->thickness;

		// We increase the bars
		$this->thickness = $this->thickness + intval($plus / $this->scale);
		$this->positionX = 0;
		$this->drawSingleBar($im, BCGBarcode::COLOR_FG);
		$this->positionX += 2;
		$this->drawSingleBar($im, BCGBarcode::COLOR_FG);
		$code1 = $this->positionX;

		// Center Guard Bar
		$this->positionX += 30;
		$this->drawSingleBar($im, BCGBarcode::COLOR_FG);
		$this->positionX += 2;
		$this->drawSingleBar($im, BCGBarcode::COLOR_FG);

		// Last Bars
		$this->positionX += 30;
		$this->drawSingleBar($im, BCGBarcode::COLOR_FG);
		$this->positionX += 2;
		$this->drawSingleBar($im, BCGBarcode::COLOR_FG);

		$this->positionX = $rememberX;
		$this->thickness = $rememberH;
	}
}
?>